The kinesin receptor kinectin is the only reported protein that binds vesicles to kinesin, and it has been shown to be localized to the cell bodies of neurons (Toyoshima et al., 1992; Kumar et al., 1995; Toyoshima and Sheetz, 1996). Its absence from the axon in contrast to the ubiquitous distribution of kinesin strongly suggests the existence of other kinectin-like proteins in neurons. In addition, in the experiments that originally identified kinectin, 20 other uncharacterized protein were found that interacted with either kinesin and vesicles. While kinectin was the most abundant of these proteins, the unexplored possibility remains that one or more of the other proteins is also a vesicle associated kinesin receptor (Toyoshima et al., 1992; Toyoshima and Sheetz, 1996). The purpose of these experiments is to identify novel kinesin receptors that may play important roles in the generation of sub-cellular organelles and in fast axonal transport. To do this, we will immunodeplete chick embryo brain of kinectin bound vesicles, and then purify kinesin binding proteins from the remaining vesicle population. Next we will microsequence and then generate monoclonal antibodies to the purified proteins, and then use the antibodies to verify the purified proteins function, to clone the purified proteins, and to determine their localization.